Source Rocks and Related Petroleum System of Chelif Basin, (Western Tellian Domain, Algeria)

HAL Id: hal-01174862

https://hal.archives-ouvertes.fr/hal-01174862

Submitted on 10 Jul 2015

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de

Source Rocks and Related Petroleum System of Chelif

Basin, (Western Tellian Domain, Algeria)

Mohamed Arab, Rabah Bracène, François Roure, Réda Samy Zazoun, Yamina

Mahdjoub, Rabi Badji

To cite this version:

lick here to view linked References

1

Source Rocks and Related Petroleum System of Chelif Basin,

1 2 3 2 4 5 6 7 3

(Western Tellian Domain, Algeria)

s

4 Mohamed Arab a, b , Rabah Bracène a , François Roure c, d , Réda Samy Zazoun e, ·,

9 10 11 12 5 13

6

14 15 16 17 18 19 7 8

Yamina Mahdjoub b and Rabi Badji a

(3) Sonatrach-Division Exploration, Avenue du 1er Novembre Bat 'C' BP 68M,

Boumerdès, Algeria.

2o 9 E-mail adress : Mohamed.arab@ep.sonatrach.dz

21 22 10

23

24

(b) Faculté des Sciences de la Terre, de la Géographie et de l'Aménagement du 25 11 Territoire, USTHB, BP 32, Bab Ez Zouar, Algiers 16111, Algeria.

26

27 12

28 29

(c) Geosciences Department, IFPEN-Institut Français du Pétrole Energies Nouvelles, 30 13 Rueil Malmaison, France.

31 32 14 33 34 35 15 36 37 16 38 39 17 40 41 42 18 43 44 19 45 46 47 20 48 49 21 50 51 52 22 53 54 23 55 56 57 24 58 59 25

(d) Tectonic Group, Utrecht University, the Netherlands.

(e *) Corresponding author: Sonatrach-Division Technologies et Développement, Avenue du 1er Novembre, Boumerdès, Algeria.

26

1. Introduction

1

2

₂₇

3 The study area lies in the external zone of the Rif-Tell or Maghrebides fold-and-thrust

4

5

28

belt, the southernmost segment of the Alpine orogeny (Durand-Delga et al., 1980; 6

7

₂₉

_{Bracene and Frizon de Lamotte, 2002; Roure et al., 2012), which trends roughly}

8 9

30

10 east-west in northern Algeria (Fig. 1 ). The Chelif Basin is a dominantly Neogene

11

12

31

trans-tensional basin located within the Northern Algerian foothills, southwest of the 13

14

₃₂

15 Kabylian ridge, which constitutes the surface expression of the paleo-suture between 16

17

33

(1) exotic terra nes of European affinities (Kabylides Crystalline Massifs and 18

19

₃₄

20 associated Mesozoic to Eocene sedimentary caver), and (2) the Tellian allochthon, 21

22

35

made up of Mesozoic basinal units derived from the former passive margin of North 23

24

₃₆

25 Africa (Benaouali-Mebarek et al., 2006, and references therein). The Neogene

26

37

27 sedimentary infill of the Chelif Basin rests on top of the allochthonous basinal 28

29

₃₈

_{Mesozoic to Paleogene carbonates and sandstones units of the southern Tellian} 30

31

39

32 allochthon.

33

34

40

Since the discovery of the small oil fields of Ain zeft and Tliouanet in the Chelif Basin 35

36

₄₁

37 in 1872, followed by Oued Gueterini in 1948 in the Hodna area, Northern Algeria 38

39

42

constitutes an interesting zone for explorationists. Besides, many oil and gas shows 40

41

₄₃

42 exist either in the Saharan Atlas, south of the Alpine thrust front, or within the Tellian

43

44

44

domain itself. The potential plays relate to Miocene compressional structures in the

45

46

₄₅

_{partially inverted foreland, in subthrust units and intra-mountain basins, as weil as in}

47

48

46

49 Triassic to Jurassic extensional structures still preserved in the foreland autochthon. 50

51

47

The aim of this paper is to (1) identify potential source rocks in the Neogene Chelif 52

53

₄₈

54 Basin, in its allochthonous Tellian substratum, as weil as in the underlying

55

51 origin of the ails in the fields, (4) assess the timing of HC migration and trapping, and

1

2 _{52 (5) define the main petroleum systems.}

3 4 5 53 6 7 54 2. Geological setting 8

1

~

55 The intra-mountain Chelif Basin (Perrodon, 1957) is located in the western part of the

11

12 56 Tellian Atlas lt is elongated in the east-west direction, with steep border faults

13

~: 57 delineating individual pull-apart basins filled by Miocene to Pliocene series (Fig. 1 ).

16

17 58 lts structure developed following the last phases of the Alpine orogeny (Alfa et al.,

18

~~ 59 1992). For instance, during the Neogene, the plate boundary between the Western

21 22 60 23 24 61 25

~~

62 28 29 63 30 31 64 32 33 34 65 35 36 66 37 38 39 67 40 41 68 42 43 44 69 45 46 70 47

Mediterranean and the Kabylides in the north and Africa in the south was a dominantly transform boundary, slab detachment and strike-slip faulting accounting for the lateral escape of the Gibraltar arc and Alboran black towards the west and Tyrrhenian-Calabrian arc towards the east (Hsü, 1971; Olivier, 1984; Thomas, 1985; Carminati et al., 1998; Spakman and Wortel, 2004, and references therein). Due to strain partitioning, numerous episodes of transpression and transtension were then recorded in the Chelif area, bath in the Tellian allochthon and underlying underthrust foreland. The tectonic studies show that the present deformation is mainly compressive with a NNW-SSE direction of shortening (Philip and Thomas, 1977; Meghraoui, 1982; Philip and Meghraoui, 1983; Meghraoui, 1988; Meghraoui and

Doumaz, 1996; fVleghraoui et al., 1996; Boudiaf et al., 1998; Domzig et al., 2006;

:~

71 Yelles-Chaouche et al., 2006; Guemache, 2010). According to Rebaï (1993), the

50

51 72 present state of regional stresses suggests that the Maghreb is subjects to a N-S

52

53 _{73 compression and acts as an indenter in its central Algerian part, the western and}

54 55

56 74 eastern parts (Morocco and Tunisia) being allowed to experience a lateral escape

57

58 75 (Piqué et al., 1998a & b ). Furthermore, based on paleomagnetic measurements, the

76 relative convergence motion between the Africa and Eurasia plates could be 1 2 ₇₇ 3 4 5 78 6 7

79

8

interpreted as a transpressional tectonic deformation model with block rotations along

the Algerian continental margin (Derder et al., 2013).

1

~

80 2.1. Geodynamic evolution and tectonic agenda

11

12 81 After the opening of the Tethys Ocean and coeval development of the northern

13 14

82

15 16 17 83 18 19 84 20 21 22 85 23 24

86

25 26 87 27 28

passive margin of Africa during the Triassic and Liassic, the rotation of the African plate as compared to Eurasia induced since the Upper Jurassic a slow convergence between the two plates. This led to a progressive closure of the former ocean, and to

the formation of the circum-Mediterranean Alpine mountains (Thomas, 1985). During

the Late Cretaceous until the Eocene, foreland inversions developed in the former rift basins of the Saharan Atlas, due to a good coupling between the plate boundary and

2 9 88 the African lithosphere, at a ti me wh en the oceanic domain was not yet tully

30

~~

89 subducted (Frizon de Lamotte et al., 2006; Bracène and Frizon de Lamotte, 2002;

33

34 90 Roure et al., 2012).

35

~~ 91 Surprisingly enough, the Tellian allochthon is made up of Upper Cretaceous to

38

39 92 Eocene basinal units derived from the distal portion of the former passive margin of

40 41 93 42 43 44

94

45

North Africa, with a basal decollement located in Triassic evaporites, with no evidence of Lower Cretaceous nor Jurassic series in between. The best interpretation

4 6 95 he re is to assume, as wh at has already be en described for the Eastern Algerian and

47 48

96

49 50 51

97

52 53 98 54 55 56

99

57

Tunisian Tell, that salt canopies made up of Triassic series were already

interstratified within the Cretaceous series of the passive margin (Vila et al., 1993;

Masrouhi and Koyi, 2012, and references therein), thus allowing a localisation of the

101 the distal portion of the African margin and on top of the southward propagating 1

2 _{102 Tellian tectonic wedge.}

3

4

5 103 The paroxysmal phase of thin-skinned deformation resulted in the overthrusting in the 6

7 104 Tellian allochthon during the Lower Miocene. As a result, Langhian series are 8

1

~

105 currently located in three distinct tectonic positions in the vicinity of the Chelif Basin 11

12 106 (Fig. 2): (1) in the autochthonous flexural basin, where the Lower Miocene deep

13

~~ 107 water turbidites rest directly on top of Upper Cretaceous blackshales in Tiaret, (2) in

16 17 108 18 19 ₁₀₉ 20 21 22 110 23 24 111 25 26 27 112 28 29 113 30

the footwall of the Tellian allochthon, where the Lower Miocene series still constitute a potential seal for the Mesozoic reservoirs of the subthrust prospects, and (3) on top of the Tellian allochthon, in a piggyback position.

After the final emplacement of the Tellian allochthon on top of its foreland domain, an episode of trans-tension occurred along the plate boundary during the Tortonian and Messinian, accounting for the formation of thrust-top pull-apart basins in the Chelif

;~

114 area (Ghazli, 2001; Roure, 2008; Roure et al., 2012), in a similar way as what has 33

34 115 been described for the Vienna Basin at the junction between the Alps and the

35

;~ 116 Carpathians (Sauer et al., 1992; Seifert, 1996), or in the Gulf of Paria between the

38

39 117 Serrania del lnterior in Eastern Venezuela in the west, and Trinidad in the east

40 41 ₁₁₈ 42 43 44 119 45 46 120 47 (Lingrey, 2007).

Since the Pliocene, there is again a good coupling between the plate boundary and the African foreland, accounting for the transpressional inversion of former normal

:~

121 faults inherited from the Tethyan rifting in the underthrust African foreland. This new

50

51 122 compressional episode has resulted in the formation of subthrust anticlines involving

52

~~ 123 the Mesozoic parautochthonous series and in the refolding of the sole thrust of the

55

56 124 overlying Tellian allochthon beneath the Chelif Basin, in a similar way as in the 57

58 125 Tempa Rossa and Monte Alpi fields of the Southern Apennines and ether nappes

126

1 2

₁₂₇

3 4 5

128

6 7

129

8 9 10 11

130

12

131

13

anticlines described in Northern Sicily (Casera et al., 1991; Roure et al., 2012), in the

eastern part of the Algerian Tell near Constantine (Vila et al., 1994), as weil as in the

tectonic windows of the Bibans and Ouarsenis Mountains (Mattauer, 1958), where

the lower plate is currently exposed to the surface due to the large a mount of tectonic

uplift and erosion.

i~

132

2.2. Neogene sedimentary infill of the Chelif Basin

16

17

133

Due to the complex tectonic evolution of the Chelif Basin, its Neogene sedimentary 18

19

₁₃₄

20 21

infill can be subdivided into 3 distinct tectonostratigraphic assemblages

(Neurdin-22

135

Trescartes, 1992 and 1995; Fig. 3): 23

24

136

At the base, the marine Lower Miocene megasequence (MSI) was still deposited 25

26

27

137

during a compressional episode, in a piggyback position on top of the still moving 28

29

₁₃₈

_{Tellian. During the Lower Miocene, the sedimentary deposits preserved on top of the} 30

31

139

32 Tellian units, and especially in the western sub-basin of the Chelif, record the 33

34

140

influence of arc-related alkaline and calc-alkaline volcanism.

35 36

₁₄₁

37 The thicker Tortonian-Messinian megasequence (MSII) was deposited during the 38

39

142

formation of the trust-top pull-apart basin, during the episode of transtension. lt still 40

41

₁₄₃

42 comprises dominantly marine siliciclastic deposits at the base, grading into mari, 43

44

144

continental siliciclastic deposits and intense volcanism, like cinerites, that are 45

46

₁₄₅

47 considered as a chronologie marker at the base of Messinian (Kieken, 197 4 and 48

146

49 1975).

50

51

147

The Plio-Quaternary sequence (MS Ill) was deposited during the reactivation and

52 53

148

54 inversion of the border faults of the Chelif Basin, coeval with the formation of 55

151

1

2 _{152 3. Results}

3

4

5 153 3.1. Source rocks characterization

6

7 154 At the scale of the Circum-Mediterranean basins and thrust-belts, numerous

8

1; 155 stratigraphie intervals have been recognized since a long time as potential source

11

12 156 rocks for hydrocarbons. This is the case for Upper Triassic bituminous limestones in

13

~: 157 Sicily and the Adriatic domain (Southern Alps, Dinarides and Albanides; Ziegler and

16

17 158 Roure, 1996, and references therein), Liassic blackshale in the Saharan Atlas in

18

~; 159 Algeria (Vi ally et al., 1994 ), in the lonian zone in the Albanides, in Epi rus in the

21

22 160 Hellenides (Karakitzios, 2013, and references therein), Cenomanian-Turonian euxinic

23

24 ₁₆₁

25 facies in the Apennines, Eocene blackshale in the Eastern Tell in Algeria, Oligocene

26

27 162 Numidian flysch in Tunisia and Sicily, as weil as Messinian series.

28

29 163 ln the Chelif area, only the Cretaceous and Cenozoic rocks of the Tellian allochthon

30

~~

164 and Neogene pull-apart basin have been investigated here, due to the current lack of

33

34 165 deep weil that would be required to document potential source rocks in the lower

35

~~ 166 plate (underthrust foreland).

38 39 167 40 41 ₁₆₈ 42 43 44 169 45 46 170 47 48 4 9 171 50 51 172 52 53 54 173 55 56 ₁₇₄ 57 58 59 175

3.1.1. Upper Cretaceous (Cenomanian to Campanian)

As is most of North Algeria, Upper Cretaceous series of the Tellian allochthon

cropping out in the vicinity of the Chelif Basin are locally preserved around the main

Neogene depocenters, either is the form of weil stratified Campanian outcrops, or as

hard blacks of Cenomanian limestones reworked in the shaley matrix of tectonic

mélanges along the sole thrust of the allochthon (Fig. 2). These Upper Cretaceous

series have been sam pied in outcrops of the northern and southern borders (Fig. 1 ).

176

mean to good. TOC varies from 1.5 to 7 % (Roure et al., 2006). TOC values varies 1

2

177

3 from 0.56 to 3% Relizane and Beni Chograne mountain, near Tliouant field the

4

5

₁₇₈

southeast, in the Dahra Mountains it ranges from 0.9 to 8.2 %. The present day

6 7

179

8 maturity shows a frozen oil window in the basin borders (outcrops) and instead a gas 9

10

180

window in wells drilled in the central part of the Neogene basin (Fig. 3). Sorne 11

12

181

13 outcrop's samples display high residual potential with Hl varying from102 to 480 mg/g

14

15

182

TOC (Fig. 4 and Tab. 1 ), they are in oil window (Tmax= 438- 443 oc), the lower Hl 16

17

₁₈₃

18

(5- 12 mg He/TOC) indicate a gas window, the Tmax is higher (574- 599 oc) (Tab.1 ). 19

20

184

21

22

₁₈₅

23 3.1.2. Oligocene Numidian series

24

186

25 The Oligocene Numidian flysch crops out also in the Tellian allochthon on both sides 26

27

₁₈₇

of the Neogene depocenters, but it may be entirely lacking beneath the whole basin

28

29

188

30 as due to the geometry of the Miocene normal faults. lt consists of grey to black 31

32

189

maris (Fig. 3) deposited in a deep water environment. lts thickness reaches up to 500 33

34

35

190

m. TOC varies from 2 to 4%, which gives an equivalent of 10 to 30 % in carbonate 36

37

191

composition. The Hl/01 diagram (Fig. 5) shows a type-Ill kerogen. However, the

38

39

₁₉₂

40 optical observation reveals amorphous sapropelic organic matter. This low potential 41

42

193

at lower maturity indicates a poor preservation of the organic matter due to oxidation 43

44

₁₉₄

_{(Fig. 5). Whole samples display low to fair TOC, ranging from 0.4 to 0.9 % and low}

45

46

195

47 maturity. ln the central part of the basin, the organic matter reached the oil window at 48

49

196

about 2100 m and a wet gas window at about 3,500 m. The environment of 50

51

₁₉₇

52 deposition, mainly controlled by the geometry of the Maghrebides-Apenninic flexural 53

54

198

basin, was probably not in direct communication with the Atlantic Ocean where up-55

56

₁₉₉

201 1 2 ₂₀₂ 3 4 5 203 6 7 204 8 9 10 205 11 12 206 13 14 207 15 16 17 208 18 19 ₂₀₉ 20 21 22 210 23 2 4 211 25 26 212 27 28 29 213 30 31 214 32 33 34 215 35

3.1.3. Lower to Middle Miocene

Their thick series of blue maris are characterized by a weakness of organic matter;

the TOC is generally lower than 0.5 % (Figs. 6 and 7), this is due mainly to a dilution

which is related to a high sedimentation rates (1 000/my) . Nevertheless, they contain

thin (decimeter-thick) layers which are limited in space with the TOCs ranging from

0.8 to 1%, like in EI-Biod and Ain Zeft area (Fig. 6 and 7). The organic matter is from

type Il marine with probably inclusion of terrestrial material (Fig. 8), regarding the

proximity of the land to the deep basin. Although the lower potential could be the

result of the thermal maturation process (Figs. 5 and 8), the high oxygen index (10=

200- 400mg C02/g COT) (Figs. 5 and 7) traduces an oxidation and thus a bad

preservation of the organic matter (Fig. 8). ln terms of maturity the deepest layers are

in gas window (Figs. 5 and 8), in the central part of the basin (EI-Biod, Nador, Akboub

and Belkheir) and in oil window in shallower areas, such as Noisy and Fornaka.

~~ 216 3.1.4. Upper Miocene series

38

39 217 The Upper Miocene series have been sampled in the northeastern (EI-Biod and Aïn

40

41 _{218 Zeft) and southwestern parts (Belkhir and Fornaka) of the basin (Fig. 1) at depths}

42 43

44 219 varying from 500 to 750 m. Apart of the Tripoli member of the Messinian where TOC

45

4 6 220 values can rea ch up to 10% or more, he average TOC values of ether Miocene

47

:

~

221 intervals range from less th an 0.5% to 1% (Fig. 5).

50

51 222 The majority of the samples in Aïn Zeft (Fig. 7), Akboub and Hellil areas display high

52

;~ 223 oxygen and lower hydrogen proportion in the organic matter (Fig. 5). The hydrogen

55

5 6 224 index is around 1 00 mg HC/g TOC (Fig.5). ln the El Bied a rea, the basal part of the

57

58 225 Upper Miocene presents a fair quality of organic matter (fig. 4 and 7). There, the

226 Hydrogen index (Hl) ranges from 100 to 150 mg HC/g TOC, the sample actually

1

2 227 recording a maturity grade at the beginning of oil window (Figs. 6 and 7). Besides,

3

4

5 228 close to the northern border of the basin near Ain Zeft and Dahra Mountain outcrop

6

7 229 samples have been analysed, they show a good organic richness, with a TOC of

8

1

~

230 1.18- 2.31% (Fig. 4 and Ta b. 1 ). However, even though the thermal indicators Tmax

11

12 231 (<430 oc) and TAI= 1.5) (Tab. 1) traduces an immaturity of the organic matter, only

13

Î~ 232 two samples display fair to excellent potential (Hl= 211 and 566 mg hc/g TOC).The

16

17 233 rest of the samples are characterized by low hydrogen indices, this is due probably to

18

~~ 234 a bad preservation or oxidation of the organic matter. Nevertheless, the oil shows

21

22 235 and the Ain Zeft accumulation is an indication that there is an efficient kitchen zone in

23

24 236 the vicinity of the area, the lack of the reliable samples does not allow establishing a

25 26

27 237 thermal maturity map. 28

29 238

30

~~

239 3.2. Oil-source rocks correlations

33

34 240 The normalized percentage compositions of the aliphatic, aromatic and NSO

35

~~ 241 fractions of each sample of rock extracts and oils are plotted in a ternary diagram

38

39 242 (Fig. 9). According to Tissot and Welte (1984), the grey area in the figure represents

40

41 _{243 typical conventional petroleum composition. The samples present a lower proportion}

42

43

44 244 of aromatics hydrocarbons (HCA) and polar products (NSO) and high saturated 45

4 6 245 hydrocarbons (HCS) (Fig. 9).

47

48

4 9 246 The graph PRfnC17 - PHfnC18 (Lumbach, 1975, in Chaouche, 1992) is used for

50

~~

247 defining the maturity and the type of organic matter of the source rock which has

53

54 248 generated oils and extracts that are analyzed by chromatography in the framework of 55

251 after the graph and humic type zone for the third sample from 1584 m (Fig. 9). At El-1

2 _{252 Biod weil the diagram shows a type-Il kerogen and lower maturity as compared to}

3 4

5 253 Akboub oils in the western area (Fig. 9). 6

7 254 An oil sample issued from Ain Zeft field (weil W3) and a hydrocarbon extract of

8

9

10 255 Messinian maris ( outcrops) have been analysed with gas chromatography and the

11

12 256 chromatograms of C14+ saturates are compared for a correlation need.The

13

~:

257 Messinian extract is characterized by a predominance of even number components

16

17 258 and a low Pr/Ph fraction (0.5) (Fig. 1 0), this is an indication of a source rock that has

18

19 _{259 been deposited in a highly reduced evaporitic environment. Besides, as indicated}

20 21

22 260 above, the samples are totally immature, C21-C35 being still present in high

23

24 _{261 proportion. The Ain Zeft oil sample displays the same distribution with also a low} 25

~~

262 Pr/Ph fraction (0.16) (Fig. 10). Moreover, the sulphur content in the present oil is

28

2 9 263 higher than 2%, meaning th at this oil was most probably generated from a type-liS

30

~~

264 organic matter. The chromatogram of Messinian extract (shows a high concentration

33

34 265 of biomarkers (Fig. 11 a). Although the oil sample is slightly mature than the extract,

35

~~ 266 the two samples seems to be similar. The absence of gas spectrometry data (GCMS) 38

39 267 could not allow a complete correlation.

40

4 1 268 The oils from Tliouanet field are very mature because they contain a higher 42

43

4 4 269 proportion of C14-C21 components (Fig. 11 c), the regular decreasing of the pick 45

4 6 270 heights, from C19 to +C30 compone nt is an indication of a marine environ ment of 47

!~

271 the organic matter, from which these oils have been generated (Fig. 11 c ).The Pr/Ph 50

51 272 fraction is 1.6; it is an indication of a highly reduced environment (Fig. 11 c).The 52

53 _{273 distribution of the extract component is the same as the one of the Tliouanet oil; the}

54 55

56 274 predomainance of nC15-nC21 components traduces the relatively higher maturity of

57

276

1 2 ₂₇₇ 3 4 5

2

78

6 7

279

8 9 10

280

11 12

281

13 14

₂₈₂

15 16 17

2

8

3

18 19

₂₈₄

20 21 22

28

5

23 24

286

25 26

2

87

27 28 29

288

30 31

289

32 33 34

290

35 36

₂₉₁

37 38 39

292

40 41

₂₉₃

42 43 44

2

94

45 46

295

47 48

296

49 50 51

297

52 53

2

98

54 55 56

299

57

reservoir in Tliounat field (basal Tortonian sandstones) comparing to the Cretaceous allochton source rock which belongs to the substratum of the Neogene Chelif basin, the migration pathways of this ail came from this Cretaceous level (Fig. 2). According to its geochemical signature, this ail is quite similar to the ails of the Oued Gueterini field farther east in the Hodna Basin, with strong affinities with extracts from Cretaceous source rocks. Because of the geometry of the Chelif Basin and their close association with the main border fault of the basin, these ails were probably generated from a deeper structural unit, with a dismigration from the subthrust parautochthous units or underthrust foreland, in a similar way as the Jurassic-sourced ails found in the Neogene reservoirs of the Vienna Basin in Austria, which were actually generated in the lower plate, thus accounting for subsequent vertical migration a cross the sole thrust of the T ellian allochthon.

3.3. Thermal modelling and hydrocarbon generation history

3.3.1. Geothermal boundary conditions

300 Another problem with 1 D models is that they can hardly account for tectonic

1

2 _{301 duplication, the Tellian allochthon recording a completely different thermal evolution}

3

4

5 302 as compared to the underthrust foreland until the Langhian, when the two demains

6

7 303 were ultimately superposed with only miner subsequent tectonic contraction.

8

9

10 304 ln this paper, the ai ms of the 1 D petroleum modelling with the Genex software was to

11

12 305 reconstruct the thermal, source rock maturation and petroleum generation in the 13

~~ 306 Neogene depocenter, with a focus on the evolution of the Neogene source rocks 16

17 307 from the post-nappe pull-apart basin. Further coupled 20 kinematic and petroleum 18

19 _{308 Thrustpack modelling has also been attempted in the past in the Chelif Basin to}

20

21

22 309 address the thermal evolution of the lower plate and exploration risk of subthrust

23

24 _{310 prospects (Sassi et al., 2006), but these results will not be detailed here, because of}

25 26

2 7 311 strong uncertainties wh en reconstructing the pre-Miocene thermal evolution of both

28

2 9 312 the Tel lian allochthon and underthrust foreland.

30

~~

313 ln any case, the North Algerian Tellian Atlas presently displays a normal crust which 33

34 314 thickness ranges from 30 to 40 km (Marillier and Mueller, 1982; Thomas, 1985).

35 36 315 37 38 3 9 316 3.3.2. Geothermal history 40

41 _{317 Acccording to Louni-Hacini et al. (1995), Neogene volcanic rocks from the}

42 43

4 4 318 northwestern coast of Algeria include calc-alkaline to shoshonitic andesites and

45

4 6 319 dacites (Sahel of Oran and M'Sirda areas) and alkaline basalts (Tafna valley). 47

!~

320 Seventeen new 4°K-40Ar ages indicate that these volcanics were emplaced during 50

51 321 two distinct periods, from 11.7 to 7.2 Ma and 4 Ma, respectively. Ali the andesites

52

53

322 and dacites were emplaced during the first period, and their trace element 54

55

56 323 characteristics are typical of subduction- and/or collision-related magmas. Du ring the 57

58

324 Late Pliocene and Quaternary, the volcanic activity occurred in the Moroccan Middle

1

2 _{325 Atlas and in Oran area in Algeria (Fig. 1 ).}

3 4

5 326 ln the Tellian thrust belt the heat flow increases rapidly towards the Mediterranean

6

7 327 Sea. lts overall pattern is comparable to that measured in the other Tertiary belts 8

9

10 328 (Takherist and Lesquer, 1989). According to these authors the present day heat flow

11

12 329 varies from 80 mW/m2 to more than 100 mW/m2 near the offshore. At the present day

13

î:

330 the geothermal gradient varies from 30-35°C/km (Normal Geothermie Gradient) to

16

17 331 more than 50°C/km (Fig. 12), two hyperthermie zones being localized in the central

18

19

332 part of the Chelif Basin, where it may be due to the local occurrence of Neogene

20 21

22 333 diapirs remobilizing the Triassic salt of the Tellian allocthon, (Fig. 2) and the coastal

23

2 4 334 zone near the Gulf of Mostaganem (i.e. in the vicinity of the neoformed Neogene

25

26

27 335 oceanic lithosphere of the offshore Algerian Basin.

28

29 336 ln the eastern part of the basin, the deduced heat flow varies from 50 mW/m2 to 85

30

;; 337 mW/m2 _{(Fig. 13a). For obvious geodynamic reasons, the heat flow model used in the}

33

34 338 present study has been considered variable through the geological time. From the 35

;~ 339 Upper Cretaceous to the Lower Miocene (main episodes of tectonic contraction), the

38

39 340 mean flow value is estimated to 50-55 mW/m2

• However, related to geodynamic and

40

41 _{341 volcanic activity of the basin, we assume a larger heat flow value since the onset of}

42

43

44 342 slab detachment and Tortonian-Messinian episode of accelerated subsidence in the

45

46 343 basin (Fenet, 1975; Bellon and Brousse, 1977; Aït Hamou, 1987; Maury et al., 2000).

47

!

~

344 Ultimately, the present day heat flow has been deduced from the geothermal gradient

50

51 345 and thermal conductivities of the sediments. The BHT corrected temperatures

52

~~

346 calibrated the present day heat flow at 85 mW/m2 _{(Fig. 13a), as estimated by}

55

56 347 Takherist and Lesquer (1989).

349 3.3.3. Reconstruction of the bu rial history

1

2 _{350 At eastern part of the study area, the Neogene series of the Chelif Basin were}

3 4

5 351 deposited on top of the Oligocene and Cretaceous Tellian allochthon (Figs. 1 and 2).

6

7 352 The Late Oligocene and Burdigalian being still characterized by deep water turbidites

8

9

10 353 along the Tellian allochthonous units underlying the Neogene depocenters of the

11

12 354 Chelif, only miner erosion occurred in this formerly basinal domain until the onset of

13

~~

355 uplift and tectonic accretion.

16

17 356 During the development of the Lower Miocene syn-compressional piggyback basin 18

~ ~ 357 (Langhian-Serravallian) and subsequent transtensional opening of the thrust-top

pull-21

22 358 apart basin (Tortonian-Messinian), the sedimentation rate was very high 250 m/Ma

23

2 4 _{359 (Fig. 13b ). Be cause of renewed trans pression al foreland inversion in post-Miocene} 25

26

27 360 times, the sedimentation rate was lower than 100m/Ma (Fig. 13b) during both the

28

29 361 Pliocene and Quaternary in the relict depocenters, most of the basin being instead

30

;~

362 impacted by inversion-related uplift and erosion.

33

34 363 ln the western area (W1 0 weil), the sedimentation rate recorded during the Upper

35

;~ 364 Cretaceous- Eocene period) is 30 m/Ma (Fig. 14 a). However, during Upper

Miocene-38

39 365 Pliocene period, this parameter reaches 80 m/Ma; this is related to the transtensional

40

4 1 366 extension of the basin (Fig. 14 a). 42

43

44 367 45

4 6 368 3.3.4. Hydrocarbon generation and expulsion histories

47

!

~

369 1 D thermal modelling has been undertaken with the Genex software on the W5 Weil

50

51 370 in the EI-Biod area and W10 to the West (Fig. 1 ). The thermal calibration of the 52

53

371 thermal model is established thanks to the measured temperatures in the weil and

54 55

5 6 372 the maturity mesurements (Ro converted values) (Fig. 13b). ln the former area, the 57

58 373 oil generation from the Middle Miocene formations (supposed source rocks) occurred

374 from 12 to 10 Ma and gas during 10- present day with a burial of 4000- 5200 m,

1

2 375 whereas, the Messenia is still immature (Fig. 13c). Besides, the Langhian supposed

3

4

5 376 source expelled oil between 8 and 5 Ma after that period only gas expulsion occurred

6

7 377 in this deeper part of the basin (Fig. 13 d).

8 9

10 378 ln the western area, there are two picks of oil expulsion, the first pick happens

11

12 379 between 12 and 8 Ma while the second one between happens at 4- 2 Ma (Piiocene)

13

~:

380 (Fig. 14b).

16

17 381 Besides, the formation of structural traps relate to the Pliocene and Quaternary

18

19 _{382 inversion, thus post-dating the Messinian episode of maximum burial. Considering} 20

21

22 383 type-li kerogen in this model, the Messinian which is the source rock of the Ain Zeft 23

24 384 oil field was not buried enough there (at 1,000 m depth) to generate hydrocarbons.

25

26

27 385 Alternatively, in the case of type-liS kerogen as is shown by the n alcanes and

28

29 386 biomarkers distribution in the rock extracts, it could generate commercial amounts of

30

~~

387 oil at lower temperatures (<50°C). A kinetic model of this organic matter would be

33

34 388 required in order to confirm such scenario. 35

~~ 389 The Upper Cretaceous series are considered as the main source rock for the Upper

38

39 390 Miocene reservoir in Tliouanet. They are probably also the source of the gas and oil 40

!~ 391 shows documented elsewhere in the Chelif Basin (Fig. 1 ). The Middle Miocene series

43

4 4 392 display sorne HC potential in the EI-Biod a rea where the Miocene reservoirs might

45

4 6 _{393 have been sourced from. The Ain Zeft he avy oil is originated from the Upper Miocene}

47

48

4 9 394 source rock which has a Iso a good generation potential in this a rea (Figs. 1, 3 and

50

51 _{395 Tab. 1 ). There are three types of traps, anticlines, roll-over structures and those} 52

53

54 396 associated to diapirs. Their age extend from Middle Miocene to Pliocene and even to 55

56 397 present day. The early charge is most likely oil whereas the most recent traps could

399 1

2 _{400 4. Discussion}

3 4

5 401 4.1. Petroleum systems analysis

6

7 402 4.1.1. Upper Cretaceous 1 basal Tortonian sandstone

8

9

10 403 ln the Tellian allochthon, the Upper Cretaceous (Cenomanian to Campanian) source

11

12 404 rocks extend only away from the Neogene depocenters, i.e. mainly south of the 13

~~ 405 Tliouanet- Relizane fields in the south (Fig. 1 a), and north of the Ain Zeft field in the

16

17 406 north, making it difficult to contribute in any way to the petroleum potential of the 18

19 _{407 basin. Axtually, due to the Tortonian-Messinian extension, Neogene series rest} 20

21

22 408 almost directly above the sole thrust of the Tellian allochthon in the central part of the

23

2 4 409 basin (Fig. 2), where coeval Upper Cretaceous source rocks are instead likely to be 25

;~

410 found at appropriate depth for HC generation in the underthrust foreland and

28

2 9 411 parautochthonous subthrust prospects. 30

;~

412 Although the presence of a thick Miocene sandstones package (200 m) in Djebel

33

34 413 Djira area, to the west, there is no petroleum perspective because of the absence of

35

;~ 414 the source rocks (Fig. 15).

38

39 415 The zone B (Fig. 15) is the most prospective thanks to the presence of reservoirs at

40

41 _{416 the base of the Upper Miocene and the presence of both Upper Cretaceous and}

42

43

44 417 Upper Miocene source rocks. However, as far as the exploration results are 45

46 418 concerned, and with the exception of the Ain Zeft accumulation, there have been only

47

~~

419 dry heles and hydrocarbon shows. The deficient parameter of the petroleum system

50

51 420 in the whole Neogene sedimentary infill of the Chelif Basin is the timing of the trap 52

53 _{421 formation as compared to hydrocarbon migration. This is the case for instance for} 54

55

56 422 Pliocene and Quaternary structures. The presence of the sm ali accumulation in 57

424 structuration or from a remigration from a deeper accumulation. Such accumulation is

1

2 _{425 not commercial.}

3

4

5 426 ln Ain Zeft, Akboub and Hellil areas, the presence of the light oils, more mature than

6

7 427 the rock extracts of the nearby source intervals, clearly require the occurrence of a

8 9

10 428 deeper kitchen and both long range lateral and vertical migration, either from deepest 11

12 429 parts of the pull-apart basin, or from the lower plate, using the main border faults of

13

i:

430 the basin to migrate from the underthrust units towards the Neogene pull-apart.

16

17 431 The zone C (Fig. 15) is the deepest part of the basin, it is characterized by a high

18

19 _{432 sedimentation rate, varying from 100 to 1000}

_mima

_{(Fig. 13b) during the Miocene.} 20

21

22 433 This might have caused dilution of the organic matter. Such sedimentological

23

24 _{434 conditions and probably the absence of upwelling streams could not favor a}

25

~

~

435 development of anoxie conditions during Miocene time.

28 29 436 30

;~

437 4.1.2. Messinian (source rock)/ Upper Miocene/Piiocene reservoirs

33

34 438 The Upper Miocene (Messinian) source rock extends along central part of the basin,

35

;~ 439 Dahra Mountain and Ai Zeft area (Fig. 15). To be effective, this petroleum system

38

39 440 would require the presence of Upper Miocene reservoirs, i.e. the basal Tortonian

40

41 _{441 sandstone and Pliocene algallimestones (Lithotamnium limestone) and relatively old}

42

43

44 442 (pre-Piiocene) structures. The generation of the hydrocarbon from Messinian source 45

4 6 443 rock is a Iso conditioned by the thickness of the Pliocene sediments (bu rial).

47

:: 444 Besides, the hydrocarbon charge of the Upper Miocene reservoirs could relate from

50

51 445 deep Neogene kitchens or again, from a vertical migration across the sole thrust of

52

~~ 446 the Tellian allochthon, from Upper Cretaceous source rocks from the lower plate.

55

449

1 2

₄

₅₀

3 4 5

451

6 7

452

8 9 10

453

11 12

454

13 14

45

5

15 16 17

456

18 19

₄₅₇

20 21 22

4

58

23 2 4

459

25 26

4

60

27 28 29

461

30 31

462

32 33 34

463

35 36

₄₆₄

37 38 39

4

6

5

40 41

₄₆₆

42 43 44

467

45 46

468

47 48

469

49 50 51

470

52 53

₄₇₁

54 55 56

4

72

57 58

₄₇₃

59

developing any commercial hydrocarbon accumulation in relationship with this play,

because of the lack of source rocks therein. Elsewhere, the Pliocene series are

thinner (because mainly of Quaternary erosion), ranging from 0 to 50 m, which is

clearly insufficient to expect any sealed reservoir there.

5. Conclusions

The Oligocene Numidian series display locally high organic contents in Sicily and

Tunisia, where they are known to account for effective petroleum systems (El Heuchi

et al., 2004; Gran ath and Casera, 2004 ). Despite the fact that no hydrocarbon field

has yet been discovered in Oligocene Numidian sandstones in Northern Algeria, the

Oligocene series of the Tellian allochthon in the vicinity of the Chelif Basin shows the

same overall characteristics, and could still constitute a target for the exploration.

ln the more than 4 km-thick pre-Messinian Miocene series, there are intervals with a

mean organic rich ness (TOC) comprised between 0.5 and 1%, but their generative

potential still remains law because of the bad preservation of the organic matter,

which is marine with slight continental contribution. The optical observation and the

law residual potential (Hl) show that there is an effect of oxidation. ln contrast, the

Tripoli member of the Messinian series displays a very high organic content, with

TOC values up to 10% or more, but law maturities (Tmax < 430°C). However, its

kerogene is of the type-liS, which could generate hydrocarbon even at law

temperatures (<50°C). Alternatively, the Upper Miocene is more buried in the main

depocenters of the Chelif Basin than in the modelled wells, implying that it could be

already in the ail window in the deepest, not yet inverted parts of the basin. The 1 D

basin modeling shows that the timing of ail generation from the Middle Miocene

474

1 2

₄₇₅

3 4 5

476

6 7 477 8 9 10

478

11 12

479

13 14

480

15 16 17

481

18 19

₄₈₂

20 21 22

483

23 2 4

484

25 26 27

485

28 29

486

30 31

487

32 33 34

488

35 36

₄₈₉

37 38 39

490

40 41

₄₉₁

42 43 44

492

45 46

493

47 48

494

49 50 51

495

52 53

₄₉₆

54 55 56

497

57

richest levels of the Middle Miocene source rocks, the ail expulsion began at 8 Ma. From 5 Ma to the Present day, mainly gas expulsion occurred. ln any case, the GC/GCMS analysis confirms the correlation between Ain Zeft ails, which contain oleanane, and Upper Miocene extracts. However, the main exploration risk for Neogene hydrocarbon systems relates to the scarcity of clastic reservoirs in the sedimentary infill of the pull-apart basin, most anticlinal structures being controlled by salt dames, with dominantly fine grain growth strata. Stratigraphie traps and sandy paleo-chanels would rather occur along the flanks of the structures or in intervening lows, but they can hardly be identified here due to the lack of 3D seismic. Plia-Quaternary anticlines related to the recent inversion of the basin are likely to post-date the episodes of maximum burial in the Miocene depocenters, even if they could host remigrated ails from aider structures, or ail escaping vertically from the substhrust units along vertical conduits such as the main border fault of the basin. Similar modes of petroleum charge is known to occur in the Vienna Basin in Austria for instance, were the ail generated in Jurassic source rocks from the lower plate have migrated upward across the Alpine nappes before to be trapped in Neogene clastics of the trust-top pull-apart basin (Sauer et al., 1992; Seifert, 1996).

499 parautochthonous structures which formed during the Plio-Quatenary episode of 1

2 _{500 transpression, making the subthrust plays a potential target. The main exploration} 3

4

5 501 risk here would relate to the possible erosion of Cretaceous platform carbonate

6

7 502 reservoirs and Albian sands of subthrust prospects prier to the development of the

8

9

10 503 Neogene foreland flexure and deposition of deep water seals, due to Late

11

12 504 Cretaceous to Eocene episodes offoreland inversion (Roure et al., 2012). 13 14 505 15 16 17 506 Acknowledgements 18

19 _{507 This work was undertaken as part of a Master Il research work realized at USTHB} 20

21

22 508 University (Aigiers). The authors wish to thank Sonatrach and Alnaft for giving us 23

24 509 access to weil data. We acknowledge M. Kaced and N. Yahi for reviewing an early

25 26

2 7 510 draft of the manuscript. We greatly benefited from discussions with A. Lassai and H. 28 29 511 Benali. 30 31 512 32 33 34 513 References 35

~~ 514 Alfa, T., Feinberg, H., Derder, M. M., Merabet, N. E., 1992. Rotations

38

39 515 paléomagnétiques récentes dans le bassin du Chélif (Algérie). Comptes Rendus de

40

41 _{516 l'Académie des Sciences, Paris, 314, Série Il, 915-922.}

42

43

44 517 45

46 518 Ait Hamou, F., 1987. Etude pétrographique et géochimique du volcanisme d'âge

47

:~

519 Miocène de la région de Hadjout (Ouest Algérois). Thèse de magister, Université des

50

523 Béhar, F., Huc, A., Da Silva, M., IFP-Sonatrach Tell-Offshore Team, 2006.

1

2 524 Geoschemistry of source rocks and oils. ln Roure F., Addoum, B. et al., Architecture

3

4

5 525 and petroleum appraisal of Northern Algeria. IFP-Sonatrach report, No 59520, Tell-6

7 526 Offshore JIP, Volume 1, 83-90, unpublished.

8 9

10 527

11

12 528 Bellon, H., Brousse, R., 1977. Le magmatisme périméditerranéen occidental: essai

13

î:

529 de synthèse. Bulletin de la Société Géologique de France 7, 469-480.

16

17 530

18

19 _{531 Benaouali-Mebarek, N., Frizon de Lamotte, D., Roca, E., Bracène, R., Faure, J. L.,}

20

21

22 532 Sassi, W., Roure, F., 2006. Post-Cretaceous kinematics of the Atlas and Tell systems 23

2 4 533 in central Algeria: Early foreland folding and subduction related deformation.

25

26

27 534 Comptes Rendus Géosciences 338, 115-125.

28

29 535 30

;; 536 Boudiaf, A., Ritz, J. F., Philip, H., 1998. Drainage diversions as evidence of

33

34 537 propagating active faults: example of the El Asnam and Thenia Faults, Algeria. Terra

35 3 6 538 Nova 10, 236-244. 37 38 39 539 40

41 _{540 Bracène, R., Frizon de Lamotte, D., 2002. The origin of intraplate deformation in the}

42

43

4 4 541 Atlas system of western and central Algeria: from Jurassic rifting to

Cenozoic-45

46 542 Quaternary inversion. Tectonophysics 357, 207-226.

47

48

543

49

50

51 544 Carminati, E., Wortel, M. J. R., Meijer, P. Th., Sabadini, R., 1998. The two-stage

52

~~ 545 opening of the western-central Mediterranean basins: a forward modelling test to a

55

56 546 new evolutionary model. Earth and Planetary Sciences Letters 160, 667-679.

548 Casera, P., Roure, F., Vially, R., 1991. Tectonic framework and petroleum potential 1

2 _{549 of the southern Apennines. ln: Spencer, A.M. (Eds.), Generation, Accumulation and} 3

4

5 550 Production of Europe's Hydrocarbons, Oxford University Press, U. K., 1991, pp.

381-6 7 551 387. 8 9 10 552 11

12 553 Derder,M. E. M., Henry, B., Maouche, S., Bayou, B., Amenna, M., Besse, J., 13

~~ 554 Bessedik, M., Belhai, D., Ayache, M., 2013. Transpressive tectonics along a major

16

17 555 E-W crustal structure on the Algerian continental margin: Blocks rotations revealed 18

~~ 556 by a paleomagnetic analysis. Tectonophysics 193, 183-192.

21 22 557 23

24 _{558 Domzig, A., Yelles, K., Le Roy, C., Deverchère, J., Bouillin, J. P., Bracène, R.,}

25 26

27 559 Mercier de Lépinay, B., Le Roy, P., Calais, E., Kherroubi, A., Gaullier, V., Savoye, B., 28

29 560 Pauc, H., 2006. Searching for the Africa-Eurasia Miocene boundary offshore western 30

~~

561 Algeria (MARADJA'03cruise). Comptes Rendus Géoscience 338, 80-91.

33 34 562 35

~~ 563 Durand-Delga, M., Fontobé, J. M., Vila J. M., 1980. Le cadre structural de la

38

39 564 Méditerranée occidentale. 26th International Geological Congress. Paris, Collection

40 41 _{565 5, BRGM, Mémoire 115, 67-85.} 42 43 44 566 45

4 6 567 El Euchi, H., Saidi, M., Fourati, L., El Makerssi, C., 2004. Northern Tunisia thrust

47

!~

568 belt: Deformation models and hydrocarbon systems. ln: Swennen, R., Roure, F. and

50

51 569 Granath, J.W. (Eds.), Deformation, fluid flow and reservoir appraisal in foreland fold-52

573 Espitalié, J., Deroo, G. and Marquis, F., 1985. La pyrolyse Rock-Eval et ses

1

2 574 applications. Revue de l'Institut Français du Pétrole 40, 563-578.

3

4

5 575

6

7 576 Fenet, B., 1975. Recherches sur I'Aipinisation de la bordure septentrionale du

8

1

~

577 Bouclier Africain, à partir de l'étude d'un élément de l'Orogenèse nord-maghrébin:

11

12 578 Les monts de Tessala du Djebel Tessala et les massifs du littoral Oranais. Doctorat

13

~: 579 d'Etat, Institut polytechnique Méditerranéen, Université de Nice, France, p. 301.

16 17 580 18 19 ₅₈₁ 20 21 22 582 23 24 583 25 26 27 584 28 29 585 30 31 586 32 33 34 587 35 36 ₅₈₈ 37 38 39 589 40 41 ₅₉₀ 42 43 44 591 45 46 592 47 48 593 49 50 51 594 52 53 595 54 55 56 596 57

Frizon de Lamotte, D., Saint-Bezar, B., Bracène, R., Mercier, E., 2000. The two main

steps of the Atlas building and geodynamics of the west Mediterranean. Tectonics,

19 (4), 740-761.

Ghazli, R., 2001. Evolution structurale et pétrolière du bassin du Chélif (Algérie du

Nord). Master Thesis, ENSPM-IFP-School, 30pp, unpublished.

Granath, J. W., Casera, P., 2004. Tectonic setting of the petroleum systems of Sicily.

ln: Swennen, R., Roure ,F. and Granath, J.W. (Eds.), Deformation, fluid flow and

reservoir appraisal in foreland fold-and-thrust belts, American Association of

Petroleum Geologists Memoir, Hedberg Series, 1, 2004, pp. 391-411.

Guemache, M. A., 2010. Evolution géodynamique des bassins sismogènes de

l'Algérois (Algérie): approche pluridisciplinaires (méthodes géologiques et

géophysiques). Thèse de Doctorat, Université des Sciences et de la Technologie

598 Hsü, K. J., 1971. Origin of the Alps and Western Mediterranean. Nature, 233, 44-48.

1 2 ₅₉₉

3

4

5 600 Karakitsios, V., 2013. Western Greece and lonian sea petroleum systems. American

6

7 601 Association of Petroleum Geologists Bulletin 97 (9), 1567-1595.

8 9

10 602

11

12 603 Lingrey, S., 2007. Cenozoic deformation of Trinidad: Foldbelt restoration in a region 13

~~ 604 of significant strike-slip. ln: Lacombe 0., Roure, F., Lavé,

J.

& Vergés,

J.

(Eds.),

16

17 605 Thrust belts and foreland basins, Frontiers in Geosciences, Springer, 2007, pp.

163-18 19 _{606 178.} 20 21 22 607 23

2 4 608 Marillier, F., Mueller, S., 1982. The western Mediterranean region as an upper-mantle

25

~~

609 transition zone between two lithospheric plates. Tectonophysics 118 (1-2), 113-130.

28 29 610

30

~~

611 Masrouhi, A., Koy,i H., 2012. Submarine "salt glacier" kinematics of Northern 33

34 612 Tunisia, a case of Triassic salt mobility in North African Cretaceous passive margin.

35

~~ 613 ln: Alsop, G.

1,

Archer, S. G, Hartley, A, Grant, N .. T, Hodgkinson, R. (Eds.), Salt

38

39 614 Tectonics, Sediments and Prospectivity. Geological Society, London, Special 40 4_{1 615 Publications, 363, 2012, pp. 579-593.} 42 43 44 616 45

4 6 617 Matta uer, M., 1958. Etude Géologique de l'Ouarsenis Orienta, Algérie, Publication du

47

!

~

618 Service de la Carte Géologique de l'Algérie, Bulletin No 17, Nouvelle Série, 543pp.

50 51 619

52 53 ₆₂₀

Maury, R.G., Fourcade, S., Coulon, C., El Azzouzi, M., Bellon, H., Goutelle, A.,

54

55

56 621 Ouabadi, A., Semroud, B., Megartsi, M., Cotton, J., Bellanteur, 0., Lounii-Hacini, A.,

57

58

622 Piqué, A., Capdevila, R., Hernandez, J., Rehault, J.P., 2000. Post-collisional

1

2 _{623 Neogene magmatism of the Mediterranean Maghreb Margin: a consequence of slab}

3

4

5 624 breakoff. Comptes Rendus de l'Académie des Sciences, Paris, 331, 159-173. 6

7 625

8 9

10 626 Meghraoui, M., 1982. Etude néotectonique de la région nord-est d'El Asnam, relation

11

12 627 avec le séisme du 10/10/1980. PhD Thesis, 3° Cycle, Université de Paris VI, France,

13

i~

628 p.190. 16

17 629

18

19 _{630 Meghraoui M., Cisternas A., Philip H., 1986. Seismotectonics of the lower Chelif}

20 21

22 631 Basin: structural background of the El -Asnam (Aigeria) earthquake. Tectonics 5 (6) , 23 24 632 809-836. 25 26 633 27 28

29 634 Meghraoui, M., Doumaz, F., 1996. Earthquake-induced flooding and paleoseismicity 30

~~

635 of the El Asnam (Aigeria) fault-related fold. Journal of Geophysical Research 101, 33 34 636 17617-17644. 35 36 637 37 38

39 638 Mekki, F., Bouslah, S., 2001. Caractérisation géochimique de l'huile d'Ain Zeft. 40

41 _{639 Sonatrach- CRD Internai Report, 195/01.2039, unpublished.}

42

43

44 640

45

46 641 Neurdin-Trecartes, J., 1992. Le remplissage sédimentaire du bassin néogène du

47

:

~

642 Chélif, modèle de référence de bassins intra-montagneux. PhD Thesis, Thèse d'Etat, 50

51 643 Académie de Bordeaux, France, p. 605. 52 53 644 54 55 56 645 57

647

1

2 _{648 Perrodon, A., 1957. Etude géologique des bassins néogènes sublittoraux de}

3

4

5 649 l'Algérie occidentale. PhD Thesis, Nancy Univ., Publication du Service de la Carte

6

7 650 Géologique de l'Algérie , Bulletin No 12, 328pp.

8 9

10 651

11

12 652 Philipe H., Meghraoui, M., 1983. Structural analysis and interpretation of the surface

13

~ ~ 653 deformation of the El As nam earthquake of October 10, 1980, geodetic determination

16

17 654 of vertical and horizontal movements. Bulletin Seismological Society of America 72,

18 l9 655 2227-2224. 20 21 22 656 23

24 657 Piqué, A., Ait Brahim, L., Ait Ouali, R., Amrhar, M., Cherroud, M., Courmelen, C.,

25

~~

658 Laville, E., Rekhiss, F., Tricart, P., 1998. Evolution structurale des domaines

28

2 9 659 atlasiques du Maghreb au Méso-Cénozoïque; le rôle des structures héritées dans la

30

;~

660 déformation du domaine atlasique de l'Afrique du Nord. Bulletin de la Société

33 34 661 Géologique de France 169 (6), 797-810. 35 36 662 37 38

3 9 663 Re baï, S., 1993. Recent tectonics in northern Tunisia: coexistence of compressive

40

41 _{664 and extensional structures. Annales TectonicCE 7, 129-141.}

42

43

44 665

45

4 6 666 Roure, F., 2008. Foreland and hinterland basins: what contrais the ir evolution ?,

47

!

~

667 Swiss Journal of Geosciences 101, 1-24.

50 51 668

52

53 _{669 Roure, F., Addoum, B. et al., (2006). Architecture and petroleum appraisal of}

54

55

56 670 Northern Algeria. IFP-Sonatrach report, 59520, Tell-Offshore JIP, Volume 1, 188pp,

57

58 671 unpublished.

672 1

2 673 Roure, F., Casero, P., Addoum, B., 2012. Alpine inversion of the North African

3

4

5 674 Margin, and delamination of its continental crust. Tectonics, 31, TC3006,

6 7 675 doi.1029/2011 TC002989. 8 9 10 676 11

12 677 Royden, L. H., 1985: The Vienna Basin: a thin-skinned pull-apart basin. ln: Biddle 13

~~ 678 K.T., and Christie-Biick N. (Eds.), Strike-slip deformation, basin formation and 16

17 679 sedimentation. SEPM Society for Sedimentary Geology, Special Publication, 37, 18 19 _{680 1985, pp. 313-338.} 20 21 22 681 23

24 682 Sassi, W., Mechti, M., Yessad, S., Roure, F., The Tell-Offshore Team, 2006. ln: 25

~

~

683 Roure, F., Addoum, B. et al., Architecture and petroleum appraisal of Northern

28

29 684 Algeria. IFP-Sonatrach report, 59520, Tell- Offshore JIP, Volume 1, 121-134,

30 31 685 unpublished. 32 33 34 686 35

36 _{687 Sauer, R., Seifert, P., Wessely, G. 1992. Guidebook to excursion in the Vienna}

37

38

3 9 688 Basin and the adjacent Alpine-Carpathian thrust belt in Au stria. Mitteilungen der

40

41 _{689 Osterreichischen Geologischen Gesellschaft, 85pp.}

42

43 44 690

45

4 6 691 Seifert, P. 1996: Sedimentary-tectonic development and Austrian hydrocarbon

47

:

~

692 potential of the Vienna Basin. ln: Wessely, G. & Liebl, W. (Eds.), Oil and gas in

50

51 693 Alpidic thrust belts and basins of Central and Eastern Europe. European Association

52

;~ 694 of Geological Enginering Special Publication, 5, 1996, pp. 331-342.

55

56 695

696 Spakman, W., Wortel, R.,

?004.

A tomographie view on Western Mediterranean

1

2 _{697 geodynamics. ln: Cavazza et al., (Eds.), The TRANSMED Atlas: The Mediterranean}

3 4

5 698 Region From Grust to Mantle, Springer, New-York, 2004. Pp. 31-52.

6

7 699

8 9

10 700 Takherist, D., Lesquer, A., 1989. Mise en évidence d'importantes variations

11

12 701 régionales de flux de chaleur en Algérie, Canadian Journal of Earth Sciences 26,

13 14 702 615- 626. 15 16 17 703 18

19 _{704 Thomas, G., 1985. Géodynamique d'un bassin intramontagneux, le bassin de Chélif}

20 21

22 705 occidental (Algérie), durant le Mio-Plie-Quaternaire. PhD, Thèse d'Etat, Université de

23

24 706 Pau et des pays de l'Adour, France, p. 594.

25 26 27 707 28

29 708 Vially ,R., Letouzey, J., Bénard F., Haddadi, N., Desforges, G., Askri, H., Boudjema,

30

~~

709 A., 1994. Basin inversion along the North African margin: The Saharan Atlas (Aigeria).

33

34 710 ln: Roure F.(Eds.), PeriTethyan Platforms, Editions Technip, Paris, 1994, pp. 79-117.

35 36 ₇₁₁

37 38

39 712 Vila, J. M., 1994. Mise au point des données nouvelles sur les terrains triasiques des

40

41 _{713 confins algéro-tunisiens: Trias allochtone, "glacier de sel" sous-marins et vrais diapirs.}

42

43

44 714 ln : Dercourt J., Tefiani M. and Vila J.M. (Eds.), Trias 93, Mémoire du Service

45 4 6 715 Géologique de l'Algérie, 6, 1994, pp. 105-152. 47 48 716 49 50

51 717 Vila, J. M., Sigal, J., Lahondère, J. C., 1993. Position en fenêtre de la série néritique

52

53 _{718 constantinoise sous la nappe de Djemila: Observations nouvelles du Djebel Mazela}

54 55

56 719 (massif du Djebel Oum Settas, Algérie du Nord-Est), Comptes Rendus de l'

57

58 _{720 Académie des Sciences, Série Il, 317, 395-401.}

721 1

2 _{722 Yelles-Chaouche, A., Boudiaf, A., Djellit, H., Bracène, R., 2006. La tectonique active}

3

4

5 723 de la région nord algérienne. Comptes Rendus Géoscience 338, 126-139.

6

7 724

8 9

10 725 Ziegler, P., Roure, F., 1996. Architecture and petroleum systems of the Alpine orogen

11

12 726 and associated basins. ln: Ziegler P. and Horvath F. (Eds.), PeriTethys, Mémoire. 2,

13

~: 727 Museum de l' Histoire Naturelle, Paris, 1996, pp. 15-46.

1 Figures captions

2 Figure 1. (a) Geological setting of Chelif Basin and weil location map and petroleum

3 results (b ).

4

5 Figure 2. Regional structural cross-section of the Chelif Basin, outlining the Neogene

6 flexural basin, the Langhian and Mesozoic series of the underthrust foreland, the

7 Tellian allochthon, and the Tortonian-Messinian series of the thrust-top pull-apart

8 basin and the main hydrocarbon kitchens and petroleum plays.

9

10 Figure 3. Typical Neogene stratigraphie and lithological section of the Chelif Basin

11 and its substratum.

12

13 Figure 4. Geochemicallog (Rock-Eval data) of Miocene section (El Biod , Weil W5).

14

15 Figure 5. Geochemical log (Rock-Eval data) of Miocene section (Ain Zeft field , Weil

16 W3).

17

18 Figure 6. Maturity indication: S2/TOC diagram of different source rocks.

19

20 Figure 7. Hl Vs. 01 diagram of Miocene organic matter, Akboub, Hellil areas and

21 outcrops samples.

22

23 Figure 8. Hl Vs. Tmax diagram of Miocene organic matter (Weil W6 and outcrops

24 samples ).

26 Figure 9. Ternary diagram HCS-HCA-NSO for oils and rock extracts.

27

28 Figure 10. Pr/nC17 Vs. Ph/nC18 graph of oil indices and rock extracts of Oligocene

29 and Miocene stratigraphie levels.

30

31 Figure 11. Gas chromatogram traces of nC14+ saturates in the source rock extracts

32 and oils.

33 (a) Oil fraction from Upper Miocene reservoir (Weil W3; Ain Zeft field).

34 (b) Messinian hydrocarbon extract (Mesinian maris from outcrops of Ain Zeft area). 35 (c) Oil fraction from Upper Miocene reservoir (Tiiouanet field).

36 (d) Upper Cretaceous hydrocarbon extract (Western Tellian domain).

37

38 Figure 12. Geothermical gradient map (°C/Km) of Chelif basin.

39

40 Figure 13. (a, b, c and d) Results of 10 Genex modelling of the bu rial history and

41 hydrocarbon generation in EI-Biod area (Weil W5).

42

43 Figure 14. (a and b) Results of 10 Genex modelling of the burial history and

44 hydrocarbon generation in Akboub a rea (Weil W1 0). 45

46 Figure 15. Extension of upper Cretaceous source rock and zonation in terms of

47 prospectivity of Upper Cretaceous (SR)/basal Tortonian (reservoir) petroleum

48 system.